A Chinese government airplane entered Japanese airspace over the disputed Senkaku Islands in the East China Sea on Thursday in the first such airspace intrusion in Japan, prompting an immediate protest from the Japanese government.

The Air Self-Defense Force scrambled F-15 fighter jets to the area after one of China’s State Oceanic Administration airplanes was spotted at 11:06 a.m. about 15 kilometers south of Uotsuri Island, one of the Japanese-administered Senkakus claimed by China, Chief Cabinet Secretary Osamu Fujimura told reporters.

It is the first-ever intrusion by China into Japanese airspace since Tokyo started tallying the number of such intrusions in 1958, according to the Defense Ministry.

Four Chinese maritime surveillance vessels entered Japanese waters around the disputed islands in Okinawa Prefecture in the morning, marking the third straight day Chinese government ships have entered the waters, the Japan Coast Guard said.